PA 3power amplifier

user manual

Musikhaus Thomann

Thomann GmbH

Hans-Thomann-Straße 1

96138 Burgebrach

Germany

Telephone: +49 (0) 9546 9223-0

E-mail: info@thomann.de

Internet: www.thomann.de

10.10.2017, ID: 382062

Table of contents

1 General information................................................................................................................................. 41.1 Further information........................................................................................................................... 51.2 Notational conventions.................................................................................................................... 61.3 Symbols and signal words............................................................................................................... 6

2 Safety instructions..................................................................................................................................... 8

3 Features....................................................................................................................................................... 15

4 Installation and starting up................................................................................................................ 16

5 Connections and controls................................................................................................................... 21

6 Technical specifications....................................................................................................................... 26

7 Plug and connection assignment.................................................................................................... 27

8 Cleaning....................................................................................................................................................... 30

9 Protecting the environment.............................................................................................................. 31

Table of contents

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1 General information

This manual contains important instructions for the safe operation of the unit. Read and followthe safety instructions and all other instructions. Keep the manual for future reference. Makesure that it is available to all those using the device. If you sell the unit please make sure thatthe buyer also receives this manual.

Our products are subject to a process of continuous development. Thus, they are subject tochange.

General information

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1.1 Further information

On our website (www.thomann.de) you will find lots of further information and details on thefollowing points:

Download This manual is also available as PDF file for you to download.

Keyword search Use the search function in the electronic version to find the topics ofinterest for you quickly.

Online guides Our online guides provide detailed information on technical basicsand terms.

Personal consultation For personal consultation please contact our technical hotline.

Service If you have any problems with the device the customer service willgladly assist you.

General information

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1.2 Notational conventions

This manual uses the following notational conventions:

The letterings for connectors and controls are marked by square brackets and italics.

Examples: [VOLUME] control, [Mono] button.

1.3 Symbols and signal words

In this section you will find an overview of the meaning of symbols and signal words that areused in this manual.

Letterings

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Signal word Meaning

DANGER! This combination of symbol and signal word indicates animmediate dangerous situation that will result in death orserious injury if it is not avoided.

CAUTION! This combination of symbol and signal word indicates a pos‐sible dangerous situation that can result in minor injury if itis not avoided.

NOTICE! This combination of symbol and signal word indicates a pos‐sible dangerous situation that can result in material andenvironmental damage if it is not avoided.

Warning signs Type of danger

Warning – high-voltage.

Warning – danger zone.

General information

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2 Safety instructions

This unit amplifies audio frequency signals for the operation of passive loudspeakers. It isdesigned for professional use only. Use the device only as described in this user manual. Anyother use or use under other operating conditions is considered to be improper and may resultin personal injury or property damage. No liability will be assumed for damages resulting fromimproper use.

This device may be used only by persons with sufficient physical, sensorial, and intellectualabilities and having corresponding knowledge and experience. Other persons may use thisdevice only if they are supervised or instructed by a person who is responsible for their safety.

Intended use

Safety instructions

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DANGER!Danger for childrenEnsure that plastic bags, packaging, etc. are disposed of properly and are notwithin reach of babies and young children. Choking hazard!

Ensure that children do not detach any small parts (e.g. knobs or the like) fromthe unit. They could swallow the pieces and choke!

Never let children unattended use electrical devices.

DANGER!Electric shock caused by high voltages insideWithin the device there are areas where high voltages may be present. Neverremove any covers.

There are no user-serviceable parts inside.

Do not use the device if covers, protectors or optical components are missing ordamaged.

Safety

Safety instructions

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DANGER!Hazardous voltageHazardous voltage may be present at cable ends and screw terminals.

The connection of screw terminals as well as all maintenance and repair work onthe electrical installation of the device must only be performed by qualified elec‐trical personnel in volt-free condition. Failure to do so may result in electric shockand risk of fire and loss of life.

By all means you have to observe all electrical safety instructions applicable at theplace of operation.

DANGER!Electric shock caused by short-circuitAlways use proper ready-made insulated mains cabling (power cord) with a pro‐tective contact plug. Do not modify the mains cable or the plug. Failure to do socould result in electric shock/death or fire. If in doubt, seek advice from a regis‐tered electrician.

Safety instructions

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CAUTION!Possible hearing damageWith loudspeakers or headphones connected, the device can produce volumelevels that may cause temporary or permanent hearing impairment.

Do not operate the device permanently at a high volume level. Decrease thevolume level immediately if you experience ringing in your ears or hearingimpairment.

NOTICE!Risk of fireDo not block areas of ventilation. Do not install the device near any direct heatsource. Keep the device away from naked flames.

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NOTICE!Operating conditionsThis device has been designed for indoor use only. To prevent damage, neverexpose the device to any liquid or moisture. Avoid direct sunlight, heavy dirt, andstrong vibrations.

NOTICE!Power supplyBefore connecting the device, ensure that the input voltage (AC outlet) matchesthe voltage rating of the device and that the AC outlet is protected by a residualcurrent circuit breaker. Failure to do so could result in damage to the device andpossibly injure the user.

Unplug the device before electrical storms occur and when it is unused for longperiods of time to reduce the risk of electric shock or fire.

Safety instructions

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NOTICE!Magnetic fieldsThe device generates strong magnetic fields that can interfere with the functionof poorly shielded devices. The strongest magnetic fields are directly above andbelow the power amplifier. Therefore, never place sensitive devices such as pre-amplifiers, radio transmission systems, or tape decks directly above or below thepower amplifier. When installing the power amplifier into a rack, you should placeit in the lowest position, and further equipment such as pre-amplifiers in thehighest position.

Safety instructions

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NOTICE!Possible damages by using an external batteryImproper handling may cause an arc or short circuit between the bare ends of alive power cable to an external battery. This can destroy the battery and there is afire hazard!

If you use an external battery for power supply, connect the power cord to thescrew terminal on the rear panel first. Then connect the free ends of the cables tothe battery poles. Pay attention to the polarity marking! To disconnect the bat‐tery, unscrew the cables on the battery first, then on the terminals of the device.

Also pay attention to the safety instructions of the battery manufacturer.

Safety instructions

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3 Features

n Flexible high-performance power stage for PA applicationn 240 W (RMS)n Inputs: XLR, 1/4" phone socket (unbalanced), RCA sockets, screw terminalsn Outputs:

– Screw terminals for loudspeakers, optionally in 4 Ω, 70 V or 100 V technology– Line output for connecting additional power stages (XLR, unbalanced 1/4" phone

socket, RCA sockets, screw terminals)n Protection circuits: DC short-circuit protection, overheat protection

Features

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4 Installation and starting up

Unpack and carefully check that there is no transportation damage before using the unit. Keepthe equipment packaging. To fully protect the device against vibration, dust and moistureduring transportation or storage use the original packaging or your own packaging materialsuitable for transport or storage, respectively.

Create all connections while the device is off. Use the shortest possible high-quality cables forall connections. Take care when running the cables to prevent tripping hazards.

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DANGER!Hazardous voltageHazardous voltage may be present at cable ends and screw terminals.

The connection of screw terminals as well as all maintenance and repair work onthe electrical installation of the device must only be performed by qualified elec‐trical personnel in volt-free condition. Failure to do so may result in electric shockand risk of fire and loss of life.

By all means you have to observe all electrical safety instructions applicable at theplace of operation.

DANGER!Electric shock caused by high voltages at the power amplifier outputThe output voltages of modern high-performance amplifiers may result in deathor serious injury.

Never touch the bare ends of loudspeaker cables when the amplifier is on.

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NOTICE!Magnetic fieldsThe device generates strong magnetic fields that can interfere with the functionof poorly shielded devices. The strongest magnetic fields are directly above andbelow the power amplifier. Therefore, never place sensitive devices such as pre-amplifiers, radio transmission systems, or tape decks directly above or below thepower amplifier. When installing the power amplifier into a rack, you should placeit in the lowest position, and further equipment such as pre-amplifiers in thehighest position.

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You can choose to either connect low-ohm loudspeakers with a total impedance of 4 Ω or ELAspeakers (70 V technology or 100 V technology). Observe the following diagram when con‐necting the loudspeakers. The connectors are located under a removable cover. Replace thiscover after connecting the speakers and before you turn on the power.

Low-ohm speakers

On the output of the amplifier, the overall impedance resulting from the individual impe‐dances of the connected speakers must not fall below the minimum allowable impedance ofthe amp's output, for this model 4 Ω. If you want to connect multiple speakers to the amplifieroutput, note the following:

n when connecting speakers in series, the impedances add up.n when connecting speakers in parallel, the reciprocal value of the total impedance is equal

to the sum of the reciprocal values of the individual impedances.

This means, for example with two speakers with the same impedance: In series connection,impedance is doubled. In parallel connection, it's halved.

ELA speakers

The total power consumption of the connected speakers must be below the maximum powerof the amplifier. We recommend a power reserve of 20 %.

Speaker connection

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The device can be supplied with 24 V DC voltage. Before connecting, ensure that the cablecross-sections are sufficient.

The device has been designed for rack mounting in a standard 19-inch rack; it occupies tworack units.

DC connection

Rack mounting

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5 Connections and controls

Front panel

Connections and controls

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1 LED panel

[POWER] This LED shows that the device is turned on.

[PROTECT] Lights up when one or more protective circuits have tripped or the device is defective.

[CLIP] Lights up when the channel is overdriven. In this case, use the [INPUT GAIN] control to reduce thesignal level until the LED goes out again.

[SIGNAL] Indicates the presence of an input signal. The higher the signal level, the faster the LED flashes.

2 [POWER]

Mains switch. Switches the device on and off.

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Rear panel

Connections and controls

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3 [DC SW]

Resettable fuse. The fuse shuts down when the power amp's current drain is too high or when the loudspeakeroutput is short-circuited. To reset, disconnect the connected speakers and turn the switch back on. If the switch tripsagain, there is a defect.

4 [POWER INPUT]

IEC chassis plug for operating voltage supply with fuse holder. Before connecting to the power supply, check that thevoltage selector on the bottom of the unit is in the correct position.

Should the fuse have blown, disconnect the unit from the power supply and replace the fuse with a new fuse of thesame type.

5 [OUTPUT]

Loudspeaker output screw terminals The connectors are located under a removable cover. Replace this cover afterconnecting the speakers and before you turn on the power.

6 [DC INPUT]

Screw terminals for the power supply with direct current (24 V), for example with an uninterrupted power supply. Ifthe mains voltage fails, the DC input is automatically engaged.

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7 [GROUND LIFT]

If hum is caused by a ground loop, you can use this switch to disconnect the connection between the earth pin of thedevice and the signal ground of the device.

8 [LINK]

Line level outputs for connecting additional devices (e.g. amplifiers, recording devices or active speakers), designedas RCA sockets, XLR chassis socket, screw terminals and 1/4" socket.

9 [MUSIC INPUT]

RCA signal input sockets, XLR chassis plug, screw terminals and 1/4" phone socket.

10 [INPUT GAIN]

Input signal gain control.

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6 Technical specifications

Power output (RMS) 240 W

Frequency response, ±1 dB 30 Hz … 20 kHz (0 / –3 dB)

Amplification control –80 dB … 0 dB

Signal-to-noise ratio > 85 dB

Total harmonic distortion @ 50 % of maximumoutput power

< 1 %

Voltage supply AC 110/230 V 50 Hz or 24 V

Fuse 110 V: 5 mm × 20 mm, 10 A, 250 V, slow-blow

230 V: 5 mm × 20 mm, 5 A, 250 V, slow-blow

Dimensions (W × H × D) 482 mm × 88,8 mm × 320 mm

Weight 10.1 kg

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7 Plug and connection assignment

This chapter will help you select the right cables and plugs to connect your valuable equip‐ment in such a way that a perfect sound experience is ensured.

Please note these advices, because especially in ‘Sound & Light’ caution is indicated: Even if aplug fits into the socket, an incorrect connection may result in a destroyed power amp, a shortcircuit or ‘just’ in poor transmission quality!

Unbalanced transmission is mainly used in semi-professional environment and in hifi use.Instrument cables with two conductors (one core plus shielding) are typical representatives ofthe unbalanced transmission. One conductor is ground and shielding while the signal is trans‐mitted through the core.

Unbalanced transmission is susceptible to electromagnetic interference, especially at lowlevels, such as microphone signals and when using long cables.

In a professional environment, therefore, the balanced transmission is preferred, because thisenables an undisturbed transmission of signals over long distances. In addition to the conduc‐tors ‘Ground’ and ‘Signal’, in a balanced transmission a second core is added. This also transfersthe signal, but phase-shifted by 180°.

Introduction

Balanced and unbalanced trans‐mission

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Since the interference affects both cores equally, by subtracting the phase-shifted signals, theinterfering signal is completely neutralized. The result is a pure signal without any noise inter‐ference.

1 Signal

2 Ground, shielding

1 Ground, shielding

2 Signal (in phase, +)

3 Signal (out of phase, –)

1/4" TS phone plug (mono,unbalanced)

XLR plug (balanced)

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Drawing and table indicate the pin assignment of an RCA plug.

1 Signal

2 Ground, shielding

RCA connection

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8 Cleaning

The fan grids of the device must be cleaned on a regular basis to remove dust and dirt. Beforecleaning, switch off the device and disconnect AC-powered devices from the mains. Use a lint-free damp cloth for cleaning. Never use solvents or alcohol for cleaning.

Fan grids

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9 Protecting the environment

For the transport and protective packaging, environmentally friendly materials have beenchosen that can be supplied to normal recycling.

Ensure that plastic bags, packaging, etc. are properly disposed of.

Do not just dispose of these materials with your normal household waste, but make sure thatthey are collected for recycling. Please follow the notes and markings on the packaging.

This product is subject to the European Waste Electrical and Electronic Equipment Directive(WEEE). Do not dispose with your normal household waste.

Dispose of this device through an approved waste disposal firm or through your local wastefacility. When discarding the device, comply with the rules and regulations that apply in yourcountry. If in doubt, consult your local waste disposal facility.

Disposal of the packaging mate‐rial

Disposal of your old device

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Notes

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Notes

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Notes

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Musikhaus Thomann · Hans-Thomann-Straße 1 · 96138 Burgebrach · Germany · www.thomann.de